Detection of Parts-Per-Million Levels of Hydrogen in Solids Using a Modified Notched Neutron Spectrum Technique

The notched neutron spectrum filter technique is a method for determining hydrogen content in metals. A modified version of this technique has been proposed and has now been tested with both experiments and calculations. This modified technique takes advantage of the angular dependence of neutrons scattered by hydrogen nuclei to increase the sensitivity of the technique by a factor of ∼ 20. An experimental accuracy of 0. 4 wppm of hydrogen in a typical 0.31-cm-thick steel sample has been obtained. The technique is also applicable to a wide variety of problems where small amounts of hydrogen in, or on, another metal or high atomic number material must be determined.